gramps vs grandad

gramps and grandad both are nouns.

Word	Noun	Adjective	Verb	Adverb
gramps	Yes	No	No	No
grandad	Yes	No	No	No

As nouns, gramps and grandad are synonyms defined as:

Other synonyms of gramps include granddad, granddaddy, grandfather, grandpa.

gramps (noun)	grandad (noun)
the father of your father or mother	the father of your father or mother